Master Electrician Exam (NEC)Special Occupancies, Equipment, and ConditionsHard
A master electrician is installing a new fire alarm system in a multi-story commercial building. The fire alarm control unit (FACU) requires a dedicated branch circuit. What is the maximum overcurrent protective device (OCPD) rating permitted for this dedicated branch circuit supplying the FACU?
- A20 amperes
- B15 amperes
- CThe OCPD rating must not exceed 20 amperes.
- D30 amperes
Show answer & explanationAnswer & explanation
Correct answer: C. The OCPD rating must not exceed 20 amperes.
NEC 760.41(B) states that the overcurrent device for the dedicated branch circuit supplying the fire alarm control unit (FACU) shall not be rated more than 20 amperes. This ensures proper protection without being overly sensitive, balancing safety and reliability for critical fire alarm functions.
Why the other options are wrong
- A. 20 amperes is the maximum permitted, but the option phrasing is not precise enough.
- B. 15 amperes is permitted, but the maximum is 20 amperes.
- D. 30 amperes is too high for the dedicated FACU branch circuit.
Fire Alarm FACU OCPD Max
The maximum overcurrent protective device (OCPD) rating permitted for the dedicated branch circuit supplying a fire alarm control unit (FACU).
- Governed by NEC 760.41(B)
- Dedicated branch circuit required.
- Maximum OCPD rating is 20 amperes.
Memory trick: Fire alarm brain (FACU) needs a 'twenty-amp' guardian, no more.